System for concentrating anti-freeze solution



My 29, 1956 s o 2,747,382

SYSTEM FOR CONCENTRATING ANTI-FREEZE SOLUTION Filed Dec. 1'7, 1952 IN! 'ENTOR.

MXSLQZM A T TOP/V6345.

SYSTEM-FOR coucrumr uc Ah TI- EEZE SQLU IQN:

Harry Sloan, Waukesha, Wis., assignor to, The Vilter Manufac uringrC o Milwaukee wis, a corporation of Wi consin Application December 17, a 1952, Serial No. 326,457

3;Clain 1s. (Ql; 62;.1 4t),)

This; invention. relates imgeneralto improvements in 5 thefart' ofwtreating anti-.freezesolutions used to prevent thetfor rnation o f7frost;upon,cooling.elements, and relates morev specifically to animprovedxsystern for; concentrating and preserving chemicalxsolutions such as aretutilize cl to defrost the cooling-.cOilsQfiairconditioning and refrigerationinstallations.

The; primary object: ofsmy present; invention is to pro vide an improved system for, treating anti-freeze solutions in order to prevent dilution her of u q b g t O excessiye moisture, and: to also eliminate waste of costly chemicals used-in producingthe solutions.

It is. common. commer ia pr ctis r. qn i n ystems for various v rues Q ;bu di gsan z hs fin ts to utilize so called spray type cooling unitswherein the fresh air. deliyere d to the conditioned; space is drawn by one or merelo s swa ns-Q 1 mQr .ngm t or co lsihmughw hiqh' sir pr ss sta tly ircu a bymm np sson and. he; a r- 9! q twhishs i r jected to; sprays pf; anti-.freezesolution; in orcler toprevent formation of frosgupon thqcgoling; surfaces. The antifreeze solution thus utilized and exposed to the air; flow, consists ;on chemicals; which are spsc eptible of absorbing considerable; moisture sufligient tomaterially weaken and mpa h 3 5Q lln? 1QfY hi Qh-m s a r t lim anstwith h nr snt ys msgsomei ths lu o o waste dua at hsi a tq ifsctir f nti na m ans for rsssv ri a he a s h m .15. r m; a esswa re dra cd-rfr m e q s, masters; asma uant q iss f. h P s-a t ii-mu e; a r ysa Ws ksn s, aadiwas s at he saluti rs- A a hait y l ast ttsn, nd. toast fet An additional important object of my present invens mrasst. a

1 flu ntaaas sn nusatmaass .Thss-s. adr th a s. iss sand. dvaata s ofthe inventionwill be apparent from the following de-.

tailed description frorn which itwilltbe apparentthatthe.

gist of the improvement is the provision of a simpleand automatically functioning system for effectively concen;

trating and for preventing waste of hygroscopic antifreeze solution usedto,defrost thecooling surfaces inref frigerated air conditioning units, by. Causing the defrosting solution to absorb excess moisture. whichis. removed before the solution is returned; to. the cooling elements for subsequent defrostingpurposes- A clear conception ofthe features constituting this invention and of the construction and operation .of a typical spray type airrconditioning unit embodying the same, may be had by referring to the drawing, accompanying-and forming apart of this.specificationwherein the various parts. are designated by suitable. reference characters.

The single figure of the drawing is a combined eleya tion and diagram of a typical, commercial. spray. type of artifioal ly refrigerated air conditioning system utilizing anti-freeze chemical, Solution. to constantly defrost the w ins oils. I

While the invention has. been shown and described hereinasbeing especially. useful in connection with re-. frigerated air conditioning unitsofia specific type, his not the intention to unnecessarily: restrict the. utility of the improved system by. virtue of; this limited embodiment; anditis also contemplated thatspecific descriptive terms used herein be given thebroadest. possible interpretation consistent with-the disclosures.

Referring totheidrawing, thetypical refrigerated air conditioning system showncomprises. in general; aniair cooling unit. having a, casing l provided. with oneor more interna l cooling elementaoncoil land with one or morevinternal rotar-y blowersfi for. drawing freshair through an extensive lower. siderinlet 4 upwardly ipastthe coils: 2 andfor delivering cooled air. through upper outlets 5 to ,the receivingspace; a compressor 6 cooperating with a heat exohanger 7. and. with. a. condenser. 3, pipesor conduits 9, 10.,- and anexpansiontor regulating valve-11 to. circulate refrigerating medium through the. cooling coils 2; a pump 12 having a suction line l3qforvreceiving anti freeze solution from,a,b asin 14 in the bottorntofrthe Casing 1 and. for deliveringtthe solution througha main pipe liandthrough nozzles 16.;associatedwith branch pipes 17,-over the externalheat transfer. surfaces ofthe Coils-2; and. instrumentalities.including another heat exchanger 18 adistillingdrunrlQ, a vacuum pump 25) and pipesfandcontrol valvesfon concentrating the solution repeatedly circulated through the nozzles- 16 by the pump 12. The.cooling unitincluding-the air'conductingcasingl, anti-freeze circulating pump 1 2, and spray nozzles 16, t together withtherefrigerating system comprising the coils 2; compressor 6', condenser-8; pipes 9, 10-, and the expansion valve l l, areiallof relatively standard and well-known construction andoperation. The anti-freeze solution which is" circulated from the basin 14*through' the spray nozzlesldby the-pump 12fl'11HSL-haVE a 'low freezing point,

and propylene glycol of proper concentration may be advantageously utilized since it-is an eifective-airsterilizing, agent, itis; harmless-when brought in contact with foods it inhibits mold growth'often found on products incold storagerooms, andritihas a desirablyhigh boiling point but, is also hygroscopic and rather costly. The liquidbasin 14in the .bottorn.of the casing is provided with a float controlled. fresh water supply valve. 22 for maintaining proper liquid level. inthis. basin, and the blowers 3 may be driven by anelectric motor 2 3jwhich also propels the anti-freeze circulating pump 12 and the vacuum pum .9 h o h belt ri 4- It is important that the. anti-freeze solution be con stantly maintained at proper strength andthat Waste of the chemical ingrediens thereof be avoided, and in order to accomplish these results a special and automatically funct oning system including the" heat exchangers 7, 18, dist1ll1ng drum 19, and vacuum pump 20, is provided. The coil of the heat exchanger 18 communicates with the antifreeze header pipe 15 through a pipe 26 havinga regulating valve 27 therein, and connects with the jacket of the refrigerant heat exchanger 7 through a pipe 28. The jacket of the heat exchanger 7 communicates through a pipe 29 with a distillation drum 19 of any suitable type and which is connected to the jacket of the heat exchanger 18 by a pipe 30, and this jacket communicates with the anti-freeze pump suction line 13 through a pipe 31. The interior of. the drum 19 communicates with the inlet of the vacuum pump 20 through a pipe 32, and a pipe 33 connects the discharge side ofthis pump either with the interior of the casing 1 past a control valve 34 or with the ambient atmosphere through a valve 35. In order to insure maintenance of proper temperatureswithin the drum 19, a thermostatically controlled electric heater 36 is provided.

When the improved anti-freeze solution concentrating system has been properly installed and the air conditioning unit is in operation, the electric motor 23 drives the blowers 3 to cause the same to draw fresh air into the casing 1 through the lower inlet 4, to produce an abundant flow of the ,air past and in contact with the cooling coils 2, and to deliver the conditioned air to the desired localities through the upper outlets 5; while the circulating pump 12 is simultaneously driven by the motor 23 to constantly withdraw anti-freeze solution through the suction line 13 from the basin 14 and to deliver the same to the spray nozzles 16 through the pipes 15, 17. The outer heat transfer surfaces of the cooling coils 2 are thus constantly maintained free of frost, but the moisture from the air which would be deposited as frost upon the cooling surfaces if no sprays were utilized, is absorbed by the hygroscopic solution which thus becomes diluted while the air is dehumidified. The compressor 6 is also operating to receive the spent refrigerant from the coils 2 through the conduit 9 and to deliver the compressed refrigerant in heated condition to the primary heat exchanger 7 from which it passes into the condenser 8 and is ultimately returned to the coils 2 through the conduit and past the expansion valve 11.

The regulating valve 27 should then be set to permit a suitable quantity of anti-freeze solution to flow through the pipe 26 to the auxilliary heat exchanger 18 and from thence to the primary heat exchanger 7 through the pipe 28. In the heat exchanger 7, the anti-freeze solution absorbs heat from the compressed and heated refrigerant -delivered from the compressor 6, and the heated solution then passes into the distilling drum 19 wherein it should be sutficiently heated to cause it to boil and to thus drive off excessive moisture absorbed by the hygroscopic solution. The thermostatically controlled heater 36 should be set to insure such boiling and distillation, and the vacuum pump 20 functions to lower the boiling point of the solution and to withdraw vapors from the drum 19 through the pipe 32 and to deliver the same either to the air stream through the pipe 33 and past the valve 34 in order to re-humidify the air, or through this pipe 33 and past the valve 35 to the atmosphere in case the humidity of the conditioned air is sufficient. The distilled and concentrated hot anti-freeze liquid is delivered from the drum 19 to the auxilliary heat exchanger 18 through the pipe 30 and serves to initially heat the anti-freeze solution withdrawn from the header pipe 15 past the valve 27 and through the pipe 26, and the concentrated water free or distilled solution is returned to the circulating pump 12 through the pipe 31 and the suction line 13.

The anti-freeze solution may thus be maintained in properly concentrated condition and waste of such solution due to overflowing of liquid from the basin 14 can be avoided, while the humidity of theconditioned air may also be effectively controlled, by merely adjusting the a regulating valves 27, 34, 35. By opening the valve 27 more of the chemical solution may be delivered through the concentrating system, and by opening the valve 34 and closing the valve 35 more moisture containing slight quantities of the solution may be delivered to the air stream, and vice versa. The heat resulting from the compression of the refrigerant by the compressor 6 and which is ordinarily wasted, may be utilized to intially heat the anti-freeze solution withdrawn from the circulating pipe 15, but any other available type of heating may be utilized in place of the heat exchangers 7, 18 and the electric heater 36 in order to insure effective distillation of the solution within the drum 19.

From the foregoing detailed description of one practical adaptation of the invention, it will be apparent that the improved system after being properly installed and adjusted, functions to automatically and accurately maintain the anti-freeze solution in concentrated condition, to eliminate waste of chemicals,'and to control the humidity of the, conditioned air. By utilizing propylene glycol as the anti-freeze solution, the slightquantities of this liquid which may be driven off with the water vapor during distillation, may be utilized to sterilize the conditioned air and to prevent mold growth in the air conditioned localities. The system is-exceedingly flexible in its adaptation and operation and comprises relatively few simple parts most of which are readily available on the open market, and while the assemblage is especially useful and advantageous as applied to air conditioning units of the spray type, it may also be utilized in conjunction with other types of cooling units utilizing other forms of antifreeze solutions. 7

It should be understood that it is not desired to limit this invention to the exact details of construction and operation of the anti-freeze solution concentrating system herein specifically shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

1. In a defrosting system for air stream refrigerated cooling surfaces, means for constantly circulating abundant quantities of hygroscopic solution having low freezing point over the air cooling surfaces to prevent frost circulating means and for distilling the withdrawn mixture under vacuum to concentrate the solution thereof, means for returning the concentrated distilled solution to said circulating means, and valve means operable to return regulated quantities of the moisture resulting from said distillation to the cooled air stream beyond said cooling surfaces and for delivering excess quantities of said moisture to the ambient atmosphere.

2. In a defrosting system for air stream refrigerated cooling surfaces, means for constantly circulating abundant quantities of hygroscopic solution having low freezing point, over the air cooling surfaces to prevent frost deposits thereon by causing the solution to absorb frost producing moisture from the air stream, means for withdrawing regulated quantities of the-frost preventing solution mixed with absorbed moisture from the solution circulating means and for distilling the Withdrawn mixture under vacuum to concentrate thesolution thereof, means forreturning the concentrated distilled solution to said circulating means, and means for returning recooling surfaces,.means forconstantly circulating abundant quantities of hygroscopic solution having low freezing pointv over the aircooling surfaces toprevent .frost deposits thereon by causing the solution to absorb frost producing moisture from the air stream, means for withdrawing regulated quantities of the frost preventing solution mixed with absorbed moisture from the solution circulating means and for subjecting the withdrawn mixture to a vacuum to separate the moisture from the concen- 5 References Cited in the file of this patent UNITED STATES PATENTS Faesch Jan. 25, Paige Mar. 1, Faget Sept. 20, Bichowsky Feb. 15, Smith June 28, Cook Mar. 7, Baker July 6, Shawhan May 27, Cummings Feb. 2, 

2. IN A DEFROSTING SYSTEM FOR AIR STEAM REFRIGERATED COOLING SURFACES, MEANS FOR CONSTANTLY CIRCULATING ABUNDANT QUANTITIES OF HYGROSCOPIC SOLUTION HAVING LOW FREEZING POINT OVER THE AIR COOLING SURFACES TO PREVENT FROST DEPOSITS THEREON BY CAUSING THE SOLUTION TO ABSORB FROST PRODUCING MOISTURE FROM THE AIR STREAM, MEANS FOR WITHDRAWING REGULATED QUANTITIES OF THE FROST PREVENTING SOLUTION MIXED WITH ABSORBED MOISTURE FROM THE SOLUTION CIRCULATING MEANS AND FOR DISTILLING THE WITHDRAWN MIX TURE UNDER VACUUM TO CONCENTRATED THE SOLUTION THEREOF, MEANS FOR RETURNING THE CONCENTRATED DISTILLED SOLUTION TO SAID CIRCULATING MEANS, AND MEANS FOR RETURNING REMOVED MOISTURE RESULTING FROM SAID DISTILLATION TO THE AIR STEAM BEYOND SAID COOLING SURFACES TO HUMIDIFY THE COOLED AIR. 